package org.apache.lucene.search;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

/** A scorer that matches no document at all. */
class NonMatchingScorer extends Scorer {
	public NonMatchingScorer() {
		super(null);
	} // no similarity used

	public int doc() {
		throw new UnsupportedOperationException();
	}

	public boolean next() throws IOException {
		return false;
	}

	public float score() {
		throw new UnsupportedOperationException();
	}

	public boolean skipTo(int target) {
		return false;
	}

	public Explanation explain(int doc) {
		Explanation e = new Explanation();
		e.setDescription("No document matches.");
		return e;
	}
}
